The digital to analog converter (DAC) is widely used for signal conversion in electronic devices. The DAC converts a digital signal to an analog signal such that the analog signal can be provided to an electronic device. A current steering DAC is a widely used DAC architecture. The current steering DAC finds application in communication systems such as cell phone or base station, image processing, wireless communications, and audio-visual systems. There is an increasing demand for high resolution and high speed current steering DAC.
The current steering DAC includes multiple independent current sources. The current steering DAC has limited linearity and resolution due to current mismatch across PVT (process voltage temperature). The existing calibration techniques include off-chip calibration and on-chip calibration. The off-chip calibration is used only once. The on-chip calibration is executed every time a chip with the current steering DAC is activated. These calibration techniques are helpful when operating conditions (PVT) does not change during real time operation.
Thus, another form of calibration technique referred to as background calibration technique is utilized. The background calibration technique is useful when the operating conditions are varying and the device with the current steering DAC is running. Thus, it is important in the background calibration technique, that the current steering DAC is calibrated independent of the operating conditions.